SAN DIEGO (UPI) -- Officials in California's San Diego County said they have been unable to find the source of a mysterious odor reported on the county's beaches.

The San Diego County Health Department said the country Environmental Services searched along the coastline but was unable to find the origin of the odor, which has been described variously as "jet fuel," bad chemical odor and fabric softener, KSWB-TV, San Diego, reported Thursday.

San Diego Fire Department spokesman Maurice Luque said the odor was first reported Wednesday afternoon and seemed to have decreased by evening as wind speeds increased.